1. Field of the invention:
This invention relates to a method for mounting semiconductor chips.
2. Description of the prior art:
In general, a method for mounting semiconductor chips in which the semiconductor chips are mounted on a circuit board by the direct-bonding technique is useful for the manufacture of thin, lightweight products such as IC cards and the like. When a large number of electrodes are present on the semiconductor chips to be mounted, the direct-bonding technique is superior to the wire-bonding technique in terms of mounting rate, mounting accuracy, and so on, so that it has been used extensively in a wide variety of applications.
The conventional method for mounting semiconductor chips by the direct-bonding technique comprises forming solder bumps projecting on the semiconductor chips or on the wiring pattern so that the electrodes of the semiconductor chips are connected electrically with the wiring pattern.
When the semiconductor chips are mounted with these solder bumps, it is necessary to mount the semiconductor chips at a fixed height with respect to the wiring pattern so that electrical shorts do not occur between the semiconductor chips on the circuit board and the wiring pattern. However, in the conventional mounting method in which these solder bumps are formed, the time-consuming processes of thin-film metal vapor deposition, metal plating, and the like are required, and these processes greatly increase the cost of production, preventing the widespread application of this method.